This is Craig Scott's letter, the brother of the first victim of the shooting that April 20th 1999 schocked America. Fifteens years later, on the anniversary, he writes to his sister's assassins

It was April 20th 1999 when 18 and 17 year old Eric Harris and Dylan Klebold of Columbine High School killed 13 people and injured 24, before taking their own lives. The images of the duo with automatic rifles that roamed the school’s halls have circled the world, especially thanks to the Oscar winning documentary Bowling for Columbine, by Michael Moore.

That day forever swallowed the almost boring tranquility of a little city just outside of Denver, Colorado, and has transformed the life of Craig Scott, a student who survived the massacre, brother of Rachel, the first victim of Harris and Klebold's murder madness. In memory of his sister, Craig and his family created a non profit organization, Rachel's Challange, to prevent violence in schools across America.

Today, after 15 years, Craig wrote a letter to the killers and asked us to publish it: «I forgive you because that's what Rachel would have done».

Erica and Dylan,It's been fifteen years since you came into our school armed to the teeth killing 13 people and wounding 24. In approaching the school, the first person you killed was my sister, Rachel Scott, she was 17. Before you killed her you asked her if she believed in God, she answered "yes" and you opened fire. It was April 20th 1999, this year the anniversary falls on Easter Sunday where my family will celebrate our time together and honor our faith. If Rachel were here today she would be painting Easter eggs with our sisters and playing with our nieces and nephews. She, at some point, would look me in the eyes and tell me to smile more and not take things too seriously. She was an incredible teenager who has changed the lives of millions all by little things she did for others and the writings she left behind in her diaries. The truth about her is that she would have forgiven you for your hateful actions, so do I.

While many people around the world watched on television of students running out of the school, police approaching, and sobbing pupils. Before the camera crew arrived, I was in the library where you were slaughtering our classmates as if it were a game or movie you had watched again and again. At gunpoint you bullied and made fun of us. Crouching under a table remaining silent, I saw you shoot two of my best friends. The last thing Isaiah heard were racial slurs. You both left the library for a few minutes giving us a chance to escape. I yelled out at the students to escape with me and helped pick up a girl who had been shot. After escaping, you returned to the library and put an end to the massacre by taking your own lives.

That day my life changed forever. The next two years I carried a lot of hate and anger fantasizing on how I would have got revenge on you, had you been alive, and at times closed myself off in isolation. It was making me more like you. Then I decided to go on a mission to South Africa. It was one of Rachel's dreams. There I met the man who enlightened me. 17 members of his family had been killed and despite the profound pain he spoke with me, he shared his story and did it with serenity. That day I understood that I had to break the chain of hate you started and the only way was to share with every one. I had to travel a long path to forgiveness to free myself from your shadows. Now not only do I feel free but I speak about a powerful story that rose out of the ashes - a message that my sister left behind. The biggest antidotes to anger and hatred are kindness and compassion. Your darkness gave light a chance to be seen.

A month before the shooting, you were in your parents' basement pointing to a camera with a gun saying, “We need to get a f**king chain reaction going here.” At the same time, one month before, my sister was in her english class writing a paper about her values and beliefs, “I have a theory that if one person will go out of their way to show compassion it will start a chain reaction of the same.” Both of you spoke of a “chain reaction” but while yours ended with suicide, Rachel’s lives on with us as we share her story with millions of kids each year. My sister’s unfairly short life continues to have a huge impact on others.

I remember you. We met once when I was in 8th grade and you were in high school. Your presence instilled fear in me. We were at a mutual friend’s house and you were on the computer looking up plans to build a pipe bomb, little did I think that a couple years later I’d find myself under a table protecting myself against such a bomb. We even played basketball together, there you seemed like "normal people".

There are those who say you started the slaughter because you were bullied and ostracized in our school. If I could go back to that day on the basketball court, I would talk to you, I would ask you why you acted the way you did and I would try to make you understand that it’s not all like it seems. I would tell you that the solitude you felt was the same that many others feel and that it all passes.

Eric and Dylan, what you did that day didn't solve anything. You didn’t do justice with those guns, you stole the dreams and futures of 13 innocent people, like my sister Rachel. Today I forgive you because I know that hate only creates hate, and I cannot let you take away my smile, you’ve already taken my sister.